1. Field of the Invention
The present disclosure relates generally to a semiconductor released-beam device, and in particular, relates to a semiconductor released-beam device having a weighted beam.
2. Description of the Related Art
Micro-electromechanical systems (MEMS) in semiconductors have arisen for various applications to sense temperature, pressure, strain, acceleration, rotation, chemical properties of liquids and gases, etc. Those MEMS structures are usually combined with other integrated circuits, such as metal oxide semiconductor (MOS) circuits or complimentary metal oxide semiconductor (CMOS) circuits, for analyzing and calculating the parameters sensed by MEMS. Therefore, the MEMS manufacturing processes are required to be compatible with the existing MOS or CMOS manufacturing processes such that the whole system is inexpensive, reliable, and compact.
Different MEMS structures in semiconductors have been proposed and developed for such various sensing purposes. For example, a released-beam sensor was proposed in U.S. Pat. No. 5,917,226 for detecting temperature variation and an integrated released-beam oscillator was proposed in U.S. Pat. No. 6,278,337. A similar released-beam sensor was also proposed in U.S. Pat. No. 6,218,209 ('209 patent) for detecting acceleration and could be applied in airbag, anti-lock braking, or ride suspension systems for automobiles or in-flight aircraft monitoring systems.